TDI Performance Issues: Troubleshooting Guide

Hello.
I have a question for you guys.
'For the past two weeks, I've been having a problem with my Audi 100 2.5 TDi (AAT).'
Performance issue .
During the trip, I no longer experienced any noticeable symptoms, not even...
if I give it full throttle .
The problem is occurring more and more frequently and is already present even after the engine has started.
The engine is running normally, but the fuel consumption has increased slightly since then.
The air filter is new. I completely disassembled and cleaned the mass airflow sensor. The car has a complete service history, as documented in its maintenance record book.

I'm looking forward to your answers.

Best regards,

Thomas D.

Have you ever seen a cat?
Is the car emitting more smoke than usual?
I would also try disabling the EGR system temporarily; it's quite possible that the EGR valve is stuck.

best regards

Hannes.

Hi,

How about we start by reading the error codes?

Best regards, Rainer.

Hello Hannes.
The tip about the EGR valve was spot on!
I got two new seals and replaced the valve.
Cleaned thoroughly with Caramba.
It's working perfectly again!!!
Thank you again...

Tommy.